Coded radiation reflective lock

ABSTRACT

An optical locking system in which a key having a plurality of zones with different reflective characteristics is scanned by infrared energy through a glass plate where the pattern of the reflective zones of the key are evaluated to open a lock. Key construction is also disclosed.

States Patent [1 1 Clark, Jr.

[ CODE!) RADIATION REFLECTIVE LOCK [75] Inventor: Charles T. Clark, Jr., Lighthouse Point, Fla.

[111 3,769,514 Oct. 30, 1973 OTHER PUBLICATIONS 73A'zPolCot'P Bh, I sslgnee on) m ompano eac Security Identification by Chase et a1., lBM Technical Disclosure Bulletin, Vol. 11, No. 7, pp. 738, 739, [22] Filed: 061. 6, 1972 December 1968.

[21] Appl. No.: 295,482 7 Y Primary Examiner-Harold A. Dixon AttomeyL. Lawton Rogers, 111 [52] 11.8. C1. 250/341, 250/349, 250/368,

2501510, 317/134, 340/149 511 m. on. H0111 47/00 [57]- ABSTRACT [58] Field at Search 70/278; 317/134; An optical locking System in which a y having a p 340/149, 227; 250/83.3 H, 341, 349, 368 rality of zones with different reflective characteristics is scanned by infrared energy through a glass plate 5 References Cited where the pattern of the reflective zones of the key UNITED STATES PATENTS are evaluated to open a lock. Key construction is also d'sclosed. 3,567,909 3/1971 Allen 340/149 A 1 3,029,345 4/1962 Douglas 317/134 30 Claims, 4 Drawing Figures /0 1 I2 W I6 OSCILLATOR COUNTER LOCK OPEN 1 IN //8 LOGK SOURCE 1/ Mill/L 20 f DETECTORS l w n ,1, 27 l g i 2 l I l l 1 J ii'um l l i L l J. J. I

STB

F 7 26 F 28 LOCK '1 CODED RADIATION REFLECTIVE LOCK BACKGROUND OF THE INVENTION The present invention relates to a locking mechanism and more particularly to an optical system for actuating a locking mechanism from a point externally of the building to which entry is desired.

Use of electromagnetic and optical scanners to read a card or other key" inserted into a slot is generally known and may be found, for example, in the operation of parking lot closures. All systems of this type suffer from the disadvantage that the slot into which the key must be placed may be obstructed by leaves, twigs, dirt and the like by children and by vandals. In addition, the combinations of such systems has not been readily modifiable.

It is accordingly an object of the present invention to obviate the deficiencies of these known systems and to provide an optical locking system and method in which the key is read through a radiation transparent window.

It is another object of the present invention to provide a novel system and method in which the combination of the mechanism may be manually modified at will.

It is yet another object of the present invention to provide a novel circuit and method for the scanning of an optical key and for the evaluation of the response thereof. i i

It is still another object of the present invention to provide a novel optical key and method of construction which is both simple and inexpensive and cannot be compromised by the inadvertent viewing with the unaided human eye.

It is yet a further object of the present invention to provide a novel system and method for operating a lock in which all of the operable parts thereof are located internally of the structure into which entry is desired.

These and many other objects and advantages of the present invention will be readily apparent to one skilled in the art to which the invention pertains from the claims and from a perusual of the following detailed description in connection with the appended drawings.

' THE DRAWINGS FIG. 1 is a functional block diagram of the system of the present invention, v

FIG. 2 is a pictorial view in elevation of the scanning window of the system of FIG. 1;

FIG. 3 is a section in elevation taken through the scanning window of FIG. 2 with the position of the optical elements schematically disclosed; and,

FIG. 4 is a plan view of one embodiment of the key of the present invention illustrating the construction thereof.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT With reference to FIG. 1, a suitable conventional os cillator H is utilized to provide a series of impulses to a suitable conventional digital counter 12 which may, for example, comprise a plurality of serially connected binary elements or flip-flops. Output signals derived from the true and false output terminals of the individual flip-flops within the counter 12 may be applied to a suitable conventional timing logic circuit 14 for generation of the timing waveforms hereinafter described. The output signal from the true output terminal of the last flip-flop of the counter 12 may be used as an OPEN signal to effect the operation of an appropriate conventional locking mechanism 16.

A timing signal TMG from the timing logic circuit 14 may be utilized to control the successive application of electrical energy from a suitable conventional source 18 to a plurality of light emitting diodes 20. The light emitting diodes may be conventional elements which produce radiant energy upon the application of electrical energy from the source 18.

As will hereinafter be described, the diodes 20 are disposed in relation to a plurality of suitable conventional radiant energy detectors 22 so that none of the plurality of detectors 22 receives radiant energy directly from any of the plurality of diodes 20. The individual detectors 22 are, however, disposed to receive radiant energy from a predetermined one of the diodes 20 should such energy be reflected from a predetermined zone on an optical key 21 hereinafter described in more detail in connection with FIG. 4. Baffles may be provided to limit the application of radiant energy from each of the diodes to a predetermined zone on the optical key 21 thereby limiting the response of an individual one of thedetectors 22 to reflected energy from a predetermined one of the diodes 20. Y

The output signals from the detectors 22 may be individually applied to the common terminal of a suitable conventional switch 24 manaully operable between a no terminal N and a yes terminal Y. The N terminals of each of the switches 24 may be connected to each other and to one input terminal of a suitable gating circuit 26. Similarly, the Y terminals of each of the plurality of switches 24 may be connected together and to one input terminal of a second suitable gating circuit 28. A strobing signal STB from the timing logic circuit 14 is applied to the other input terminal of both of the gating circuits 26 and 28 and the output terminals thereof connected to provide a LOCK signal to the reset input terminal R of the counter 12.

In operation from an initial reset position, the counter 12 through the timing logic circuit 14 successively applies power from the source 18 to each of the light emitting diodes 20. One of the detectors 22 is associated with each of the diodes 20 in a relationship to receive radiant energy reflected from an optical key 21. Each of the detectors 22 is shielded from direct radiation from all of the diodes 20 and from reflective radiation from all but the single diode with which it is associated. Thus, the diodes 20 may be successively pulsed to emit radiation in a predetermined order which, because of the predetermined spatial positioning of the diodes, provides a predetermined pattern of zone illumination.

As will hereinafter be explained in greater detail, the optical key 21 may be provided with a corresponding plurality of zones such that each zone reflects radiant energy from one of the diodes 20 to the detector 22 associated therewith. By masking or otherwise eliminating the reflective characteristics of selected zones on the surface of the key 21, the pattern of reflective zones on the surface of the key will produce a corresponding pattern of detector 22 illumination.

With continued reference to FIG. 1, the switch 24 on the right hand side of the switch matrix is illustrated in the no or N position and the switch 24 on the left hand side of the switch matrix is illustrated in the yes" or Y position. All of the switches 24 are manually positioned to thereby set the pattern or combination of the locking mechanism. The detection of radiant energy by any'detector having the associated switch in the N position will produce an electrical impulse which is passed through the switch 24 to the gating circuit 26."

- sition, a LOCK signal is generated indicating an improper pattern' and the counter 12 is reset. If the interrogated zone of the key 1 does not provide an impulse when the switch 24 for that zone is in the'Y position, the LOCK signalwill also be generated to reset the counter 12. v I

Thus, the timing logic circuit'14 enables by the application of the STB signal the gating circuits 26 and 28 in timed relationship to the pulsing of the light emitting diodes 20. Should a pulse be detected by any one of the detectors 22-having the associated one of the switches 24 preset in the N position, then the LOCK signalwill be generated. Likewise, the failure of one of the detectors 22 to provide an impulse when the switch 24 is in the Y position will produce the LOCK-signal to reset the counter 12. Through this logic, the counter 12 may be advanced without resetting only when the reflective characteristics of the zones-of the key 21 correspond individually to the positions of the switches 24. Should the counter 12 be advanced to the last position thereof without reset, the counter will produce the OPEN signal for operation of the locking mechanism 16.

With reference now to FIGS. 2 and 3 an opening 29 may be provided from the inside of an external wall and the opening covered by one-quarter inch thick sheet 30 of plate glass or other radiant energy transparent material. having the desired structural characteristics. Any suitable conventional means such as a metallic plate 32 and a plurality of threaded fasteners 34 may be utilized to mount the sheet 30 over the opening. Thus, a conve- 4 desired reflective pattern by exposure of the underlying sheet 40. The sheet 42 may be coveredby a sheet of material having an arrow 46 or other appropriate indi-.

cia for indicatingthe desired key orientation with respect to the window. The sheet 44 is desirably opaque to the unaided human eye thereby obsuring the pattern of the radiant energy reflective zones and may be laminated in a transparent synthetic material to protect the key from accidental abuse.

ADVANTAGES AND SCOPE OF THE lNVENTlON From the foregoing description of the preferred embodiment, many of the advantages of the present invention will be readily apparent. For example, the optical keys may take any suitable form so long as the desired pattern of energy reflective and energy absorptive zones is produced. The use of the radiant energy emitted in the infrared frequency band permits the masking of the radiant energy reflective and absorptive zones to the unaided human eye so that the pattern of the lockthe desired structural'strength and obviates the necesnient window is provided against which the optical key late all of the detectors 22 from reflective radiation from any one of the diodes 20 other than the particular one with which it is associated. Thus, the presence of a reflective material at the zone in the window corresponding to the one of the diodes 20 being pulsed will optically couple the radiant energy from that diode to the associated detector. Likewise, the absence of reflective material at the zone against which radiant energy from the diode being pulsed will produce no output signal from the associatedone of the detectors.

With reference to FIG. 4, the optical key may be configured to register with the window illustrated in FIGS.

sity for an openinginto which may be obstructed by children or vandals.

The scanning rate of the key is the frequency of the output signal from the oscillator which drives the counter to pulse the energy radiators and may be sufficiently fast to interrogate the entire key several times during the brief interval necessary to position the key against the window and to remove the key therefrom.

Moreover, the ease with which the predetermined pattern may be changed internally of the building greatly reduce the likelihood of the successful use by an intruder of a found or stolen key. Upon the reporting of the loss of theft of a key, toggle switches may be quickly used to reset the combination of the lock and new keys issued to the appropriate parties. The simplicity andinexpensiveness of the keys permits the rapid replacement thereof as often as desirbed.

The present invention may thus be embodied in'other specific forms without departing from the spirit or essential characteristics thereof. The presently disclosed embodiments are therefore to be considered in all re spects as illustrative and not restricitive, the scope of the invention being-indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

2 and 3. The key 21 may be laminated in construction 6 What is claimed is:

1. A method of interrogating an optical key to operate a locking mechanism comprising the steps of:

a. providing a key with a plurality of radiant energy reflective zones and a plurality of radiant energy absorptive zones;

b. positioning the key in a predetermined position relative to a scanning device;

c. directing radiant energy toward each of the predetermined plurality of zones on the surface of the optical key in a predetermined sequence;

d. detecting thepattern of radiant energy reflective zones on the optical key by evaluating the sequence in which radiant energy is reflected from said zones; 7 e. evaluating the detected pattern with respect to a predetermined pattern; and, f. operating a locking mechanism responsively to the evaluation. 2. The method of claim 1 wherein the radiant energy includes energy in the infrared frequency band.

3. The method of claim 2 wherein the radiant energy reflective zones are not distinguishable by the unaided human eye from zones which are not radiant energy reflective.

4!. The method of claim 3 wherein the optical path between the key and the detectors includes glass having a thickness of at least one-quarter inch.

5. The method of claim 1 wherein the optical path between the key and the detectors includes glass having a thickness of at least one-quarter inch.

6. Themethod of claim 5 wherein the radiant energy reflective zones are not distinguishable by the unaided human eye from zones which are not radiant energy reflective.

7. The method of claim 1 wherein the radiant energy reflective zones are not distinguishable by the unaided human eye from zones which 'are'not radiant energy reflective.

8. A method of evaluating an optical key comprising the steps of:

a. periodically advancing .a counter;

b. emitting radiant energy in response to counter advancement to illuminate in a predetermined order a plurality of zones of the key;

c. detecting the pattern of radiant energy reflected from the illuminated zones; and,

d. resetting the counter in response to the detection of an improper reflection pattern, the counter providing a unique signal upon advancement without reset through a predetermined number of advance ments.

9. The method of claim 8 wherein the reflection from each individual emission of radiant energy is evaluated in response to counter advancement.

10. The method of claim 9 wherein the radiant energy includes energy in the infrared frequency band; and,

wherein the key to be evaluated includes means to prevent detection of the reflective pattern by the unaided human eye.

1 l. A method of evaluatingan optical key comprising the steps of:

a. illuminating in a predetermined pattern a plurality of zones of an optical key with radiant energy, at least one of the zones being reflective;

b. individually detecting radiant energy reflected from each zone of the key;

c. evaluating the reflection from each zone of the key individually in the sequence. in which illuminated; and,

d. providing a unique signal upon the successful evaluation of a predetermined number of individua zones of the key.

112. The method of claim 11 wherein the radiant energy is reflected through material at least one-quarter inch thick.

13. The method of claim l2 wherein the radiant energy includes energy in the infrared frequency band; and,

wherein the key to be evaluated includes means to prevent detection of the reflective pattern by the unaided human eye.

14. The method of making an optical key comprising the step of:

a. providing a first sheet having predetermined reflective charac-teristics;

b. providing a second sheet overlying the first sheet,

the second sheet having significantly different reflective characteristics and being selectively apertured to expose the first sheet to reflect radiant energy of predetermined characteristics passed through apertures in the second sheet;

c. providing a third sheet overlying the second sheet, the third sheet being opaque to the unaided human eye but able to pass radiant energy of predetermined characteristics therethrough; and,

d. forming thefirst, second, and third sheets into a unitary structure.

15. The method of claim 14 wherein the first sheet is white in color;

wherein the second sheet is dark in color; and,

wherein the third sheet will pass radiant energy in the infrared frequency band.

16. An optical lock system comprising:

a generally planar key having a plurality of zones of significantly different reflective characteristics;

a sheet of radiant energy pervious material;

means on one side of said sheet for scanning with radiant energy said key when positioned against the other side of said sheet, said means including a plurality of diodes each in a predetermined relationship to said sheet, an oscillator, and a counter advanced by said oscillator to effect the application of electrical energy to said diodes in a predetermined manner;

a lock; and,

detector means on said one side of said sheet responsive to radiant energy reflected through said sheet from said key for operation of said lock.

17. The system of claim 16 wherein the radiant energy includes energy in the infrared frequency band.

18. The system of claim 17 wherein the reflective characteristics of said zones are not distinguishable by the unaided human eye.

19. The system of claim 18 wherein said sheet is glass not signi-ficantly less than one-quarter inch in thickness.

20. The system of claim 16 wherein said detector means includes:

a plurality of radiation responsive elements associated one each with said diodes;

means for shielding all of said elements from direct radiation from any of said diodes and for shielding all of said elements from reflective energy from all but a predetermined one of said diodes;

switch means for establishing a desired pattern of reflective zones; and,

logic circuit means for individually evaluating the response of each of said elements against the desired reflectivity and to reset said counter upon an undesired response, said lock being operable in response to the advancement of said counter through a predetermined number of advancements.

21. The system of claim 16 wherein said detector means includes:

a plurality of radiation responsive elements associated one each withsaid diodes; means for shielding all of said elements from direct radiation from any of said diodes and for shielding 8 of correct evaluations to provide a unique signal. 25. An optical key for use with-a'source and detector of radiant energy comprising:

a first sheet having predetermined radiant energy reall of said elements from reflective energy from all '5 flective charac-teristics;

but a p rmin One Of Saidv d a second sheet overlying the first sheet, the second switch means for establishing a desired pattern of resheet having significantly different radiant energy flective zones; and, reflective characteristics and being selectively aplogic circuit means fo indivi l y evaluating the ertured to expose the first sheet'to radiation passed sponse'of each of said elements against the desired 10 h h h apertures i id Second sheet;

reflectivity to reset said counter upon an undesired a third sheet overlying the second sheet, the third response, said lock being operable in response to the advancement of said counter through a predetermined number of advancements. 22. An optical lock system for an enclosure closure comprising: I

a generally planar key having a plurality of zones of significantly different reflective characteristics arranged a predetermined pattern; a sheet of material pervious to radiantenergy within a predetermined band of frequencies and integral with the enclosure inproximity to the closure; means on the interior side of said sheet for scanning the zones of said key in a predetermined pattern with radiant energy when said key is positione against the exterior side of said sheet; v a lock for the closure; and, detector means on the interior side of said sheet responsive to radiant energy within said frequency band and originating interiorly of the enclosure, passed through said sheet and reflected back through said sheet from said key when positioned exteriorly of the enclosure for operating said closure lock. 23. The system of claim 22 wherein said scanning means includes a plurality of diodes each in a predetermined relationship relative to the zones of said sheet, an oscillator, and a counter advanced by said oscillator to effect the application of electrical energy to said diodes in a predetermined manner; and,

wherein said detector means includes a plurality of radiation responsive elements associated one each with said diodes, means for shielding all of said elements from direct radiation from any of said diodes and for shielding all of said elements from reflective energy from all but a predetermined one of said diodes, switch means for establishing a desired pattern of reflective zones, and logic circuit means for individually evaluating the response to each of said elements against the desired pattern of reflective zones to reset said counter upon an undesired response, said closure lock being operable in response to the advancement of said counter through a predetermined number of advancements. 24. Apparatus for evaluating an optical key through a sheet of radiant energy pervious material comprising:

means on one side of the sheet for scanning with radisheet being opaque to the unaided human eye but able to pass radiant energy of predetermined characteristics therethrough from a source external to the key to said first sheet, and to pass radiant energy of the same predetermined characteristics reflected from said first sheet to an external detector, said sheets being formed into a unitary structure.

26. The key of claim 25 wherein a significantly different reflective characteristic of said first and second sheets is reflectiveness to radiant energy in the infrared frequency band.

27. A method of operatinga locking mechanism for an enclosure closure without compromising the integrity of the enclosure comprising the steps of:

a. providing a key with a plurality of radiant energy reflective zones and a plurality of radiant energy absorptive zones arranged in a predeter-mined pattern;

b. positioning the key in a predetermined position relative to an enclosure defining member exteriorly thereof;

0. directing radiant energy from a source interiorly of the enclosure defining member through the enclosure defining member toward each of the predetermined plurality of zones on the surface of the optical key in accordance with the predetermined pattern;

d. detecting interiorly of the enclosure defining member the pattern of radiant energy reflective zones on the optical key by evaluating the reflectivity of each of the zones in the predetermined pattern;

e. evaluating the detected pattern with respect to a 45 predetermined pattern; and,

f. operating a locking mechanism responsively to the pattern evaluation.

28'. The method of claim 27 wherein the enclosure defining member is glass. having a thickness of at least one-quarter inch.

29. The method of claim 28 wherein the optical key is evaluated by the steps of:

periodically advancing a counter;

emitting radiant energy in response to counter ada plurality of zones of the key; and, resetting the counter in response to the detection of vancement to illuminate in a predetermined order means on the same side of the sheet for individually evaluating the reflectiveness of eachof the scanned zones and responsive to a predetermined number from each individual emission of radiant energy is evaluated in response to counter advancement. 

1. A method of interrogating an optical key to operate a locking mechanism comprising the steps of: a. providing a key with a plurality of radiant energy reflective zones and a plurality of radiant energy absorptive zones; b. positioning the key in a predetermined position relative to a scanning device; c. directing radiant energy toward each of the predetermined plurality of zones on the surface of the optical key in a predetermined sequence; d. detecting the pattern of radiant energy reflective zones on the optical key by evaluating the sequence in which radiant energy is reflected from said zones; e. evaluating the detected pattern with respect to a predetermined pattern; and, f. operating a locking mechanism responsively to the evaluation.
 2. The method of claim 1 wherein the radiant energy includes energy in the infrared frequency band.
 3. The method of claim 2 wherein the radiant energy reflective zones are not distinguishable by the unaided human eye from zones which are not radiant energy reflective.
 4. The method of claim 3 wherein the optical path between the key and the detectors includes glass having a thickness of at least one-quarter inch.
 5. The method of claim 1 wherein the optical path between the key and the detectors includes glass having a thickness of at least one-quarter inch.
 6. The method of claim 5 wherein the radiant energy reflective zones are not distinguishable by the unaided human eye from zones which are not radiant energy reflective.
 7. The method of claim 1 wherein the radiant energy reflective zones are not distinguishable by the unaided human eye from zones which are not radiant energy reflective.
 8. A method of evaluating an optical key comprising the steps of: a. periodically advancing a counter; b. emitting radiant energy in response to counter advancement to illuminate in a predetermined order a plurality of zones of the key; c. detecting the pattern of radiant energy reflected from the illuminated zones; and, d. resetting the counter in response to the detection of an improper reflection pattern, the counter providing a unique signal upon advancement without reset through a predetermined number of advancements.
 9. The method of claim 8 wherein the reflection from each individual emission of radiant energy is evaluated in response to counter advancement.
 10. The method of claim 9 wherein the radiant energy includes energy in the infrared frequency band; and, wherein the key to be evaluated includes means to prevent detection of the reflective pattern by the unaided human eye.
 11. A method of evaluating an optical key comprising the steps of: a. illuminating in a predetermined pattern a plurality of zones of an optical key with radiant energy, at least one of the zones being reflective; b. individually detecting radiant energy reflected from each zone of the key; c. evaluating the reflection from each zone of the key individually in the sequence in which illuminated; and, d. providing a unique signal upon the successful evaluation of a predetermined number of individual zones of the key.
 12. The method of claim 11 wherein the radiant energy is reflected through material at least one-quarter inch thick.
 13. The method of claim 12 wherein the radiant energy includes energy in the infrared frequency band; and, wherein the key to be evaluated includes means to prevent detection of the reflective pattern by the unaided human eye.
 14. The method of making an optical key comprising the step of: a. providing a first sheet having predetermined reflective characteristics; b. providing a second sheet overlying the first sheet, the second sheet having significantly different reflective characteristics and being selectively apertured to expose the first sheet to reflect radiant energy of predetermined characteristics passed through apertures in the second sheet; c. providing a third sheet overlying the second sheet, the third sheet being opaque to the unaided human eye but able to pass radiant energy of predetermined characteristics therethrough; and, d. forming the first, second, and third sheets into a unitary structure.
 15. The method of claim 14 wherein the first sheet is white in color; wherein the second sheet is dark in color; and, wherein the third sheet will pass radiant energy in the infrared frequency band.
 16. An optical lock system comprising: a generally planar key having a plurality of zones of significantly different reflective characteristics; a sheet of radiant energy pervious material; means on one side of said sheet for scanning with radiant energy said key when positioned against the other side of said sheet, said means including a plurality of diodes each in a predetermined relationship to said sheet, an oscillator, and a counter advanced by said oscillator to effect the application of electrical energy to said diodes in a predetermined manner; a lock; and, detector means on said one side of said sheet responsive to radiant energy reflected through said sheet from said key for operation of said lock.
 17. The system of claim 16 wherein the radiant energy includes energy in the infrared frequency band.
 18. The system of claim 17 wherein the reflective characteristics of said zones are not distinguishable by the unaided human eye.
 19. The system of claim 18 wherein said sheet is glass not significantly less than one-quarter inch in thickness.
 20. The system of claim 16 wherein said detector means includes: a plurality of radiation responsive elements associated one each with said diodes; means for shielding all of said elements from direct radiation from any of said diodes and for shielding all of said elements from reflective energy from all but a predetermined one of said diodes; switch means for establishing a desired pattern of reflective zonEs; and, logic circuit means for individually evaluating the response of each of said elements against the desired reflectivity and to reset said counter upon an undesired response, said lock being operable in response to the advancement of said counter through a predetermined number of advancements.
 21. The system of claim 16 wherein said detector means includes: a plurality of radiation responsive elements associated one each with said diodes; means for shielding all of said elements from direct radiation from any of said diodes and for shielding all of said elements from reflective energy from all but a predetermined one of said diodes; switch means for establishing a desired pattern of reflective zones; and, logic circuit means for individually evaluating the response of each of said elements against the desired reflectivity to reset said counter upon an undesired response, said lock being operable in response to the advancement of said counter through a predetermined number of advancements.
 22. An optical lock system for an enclosure closure comprising: a generally planar key having a plurality of zones of significantly different reflective characteristics arranged in a predetermined pattern; a sheet of material pervious to radiant energy within a predetermined band of frequencies and integral with the enclosure in proximity to the closure; means on the interior side of said sheet for scanning the zones of said key in a predetermined pattern with radiant energy when said key is positioned against the exterior side of said sheet; a lock for the closure; and, detector means on the interior side of said sheet responsive to radiant energy within said frequency band and originating interiorly of the enclosure, passed through said sheet and reflected back through said sheet from said key when positioned exteriorly of the enclosure for operating said closure lock.
 23. The system of claim 22 wherein said scanning means includes a plurality of diodes each in a predetermined relationship relative to the zones of said sheet, an oscillator, and a counter advanced by said oscillator to effect the application of electrical energy to said diodes in a predetermined manner; and, wherein said detector means includes a plurality of radiation responsive elements associated one each with said diodes, means for shielding all of said elements from direct radiation from any of said diodes and for shielding all of said elements from reflective energy from all but a predetermined one of said diodes, switch means for establishing a desired pattern of reflective zones, and logic circuit means for individually evaluating the response to each of said elements against the desired pattern of reflective zones to reset said counter upon an undesired response, said closure lock being operable in response to the advancement of said counter through a predetermined number of advancements.
 24. Apparatus for evaluating an optical key through a sheet of radiant energy pervious material comprising: means on one side of the sheet for scanning with radiant energy an optical key on the other side of the sheet through a plurality of zones of the sheet; means on the same side of the sheet for detecting radiant energy reflected through the scanned zones from the other side of the sheet; and, means on the same side of the sheet for individually evaluating the reflectiveness of each of the scanned zones and responsive to a predetermined number of correct evaluations to provide a unique signal.
 25. An optical key for use with a source and detector of radiant energy comprising: a first sheet having predetermined radiant energy reflective characteristics; a second sheet overlying the first sheet, the second sheet having significantly different radiant energy reflective characteristics and being selectively apertured to expose the first sheet to radiation passed through the apertures in said second sheet; a third sheet overlying thE second sheet, the third sheet being opaque to the unaided human eye but able to pass radiant energy of predetermined characteristics therethrough from a source external to the key to said first sheet, and to pass radiant energy of the same predetermined characteristics reflected from said first sheet to an external detector, said sheets being formed into a unitary structure.
 26. The key of claim 25 wherein a significantly different reflective characteristic of said first and second sheets is reflectiveness to radiant energy in the infrared frequency band.
 27. A method of operating a locking mechanism for an enclosure closure without compromising the integrity of the enclosure comprising the steps of: a. providing a key with a plurality of radiant energy reflective zones and a plurality of radiant energy absorptive zones arranged in a predetermined pattern; b. positioning the key in a predetermined position relative to an enclosure defining member exteriorly thereof; c. directing radiant energy from a source interiorly of the enclosure defining member through the enclosure defining member toward each of the predetermined plurality of zones on the surface of the optical key in accordance with the predetermined pattern; d. detecting interiorly of the enclosure defining member the pattern of radiant energy reflective zones on the optical key by evaluating the reflectivity of each of the zones in the predetermined pattern; e. evaluating the detected pattern with respect to a predetermined pattern; and, f. operating a locking mechanism responsively to the pattern evaluation.
 28. The method of claim 27 wherein the enclosure defining member is glass having a thickness of at least one-quarter inch.
 29. The method of claim 28 wherein the optical key is evaluated by the steps of: periodically advancing a counter; emitting radiant energy in response to counter advancement to illuminate in a predetermined order a plurality of zones of the key; and, resetting the counter in response to the detection of an improper reflection pattern, the counter providing a unique signal to operate the locking mechanism upon advancement without reset through a predetermined number of advancements.
 30. The method of claim 29 wherein the reflection from each individual emission of radiant energy is evaluated in response to counter advancement. 